1. Field of the Invention
The present invention relates to a slider for a slide fastener, and particularly, relates to a slider for a slide fastener, whereby attachment strength of a pull is improved, excellent ruggedness is realized for a long period, and an excellent assembly characteristic can be acquired.
2. Description of the Related Art
Conventionally, a slider for a slide fastener to be attached to an opening, for example, of cloths, a bag and the like is used in many cases. Basically, a slider for a slide fastener comprised three members, namely, a slider body having upper and lower blades, whose front ends are coupled by a diamond at a predetermined interval; a pull; and a pull holding body for movably and rotationally holding the pull between the pull and an upper surface of the slider body.
For example, an example of such a slider is disclosed in Japanese Patent Application Publication (JP-B) No. 60-30201. The slider disclosed in this publication is provided with hook portions at a front surface of a front post portion and a rear surface of a rear post portion, the front and rear post portions being built back and forth of the upper surface of an upper blade of the slider body; and provided with engaging pieces on inner surfaces of front and rear side wall portions of a pull holding body made of a platy cover body having a flat upper wall portion and the front and rear side wall portions. In a pull housing space portion that is formed between the opposed faces of the front and rear post portions, a pivot of the pull is movably mounted so that the hook portions and the engaging pieces are elastically engaged and fixed with each other.
The opposed faces of the front and rear post portions are respectively formed on V-shaped inclined faces that are gradually separated upward, and a tractive force from lateral and oblique sides of the pull acts with being drawn upward of the pull holding body along the V-shaped inclined face of the front post portion or the rear post portion. Therefore, the more the engaging pieces of the pull holding body pull up the hook portions of the front and rear post portions, the more the engaging pieces hold the hook portions strongly, and this makes it possible to sufficiently secure engagement of the slider body and the pull holding body.
In addition, linear concave groove portions are formed from proximal ends at sides of the hook portions of the front and rear post portions to the front and rear edges of the upper blade and at the same time, the lower surfaces of the engaging pieces of the pull holding body are formed as horizontal faces, and these horizontal faces are interiorly fit in the concave groove portions to be supported and fixed thereto. Thereby, it is possible to prevent a horizontal oscillation of the pull holding body, and further, the engaging pieces of the pull holding body and the hook portions of the front and rear post portions are reliably fitted and secured, so that it is possible to prevent the slider body and the pull holding body from being detached by the tractive force from the lateral and oblique sides of the pull.
On the other hand, as another example of the pull holding body for the slider for a slider fastener, in place of the above-described platy pull holding body for movably holding the pull, a pull holding body made of a rectangular box body having a ceiling wall portion, front and rear side wall portions, and right and left side wall portions, on which a notch is formed at its center portion, is observed.
As an example of a slider having this kind of pull holding body, for example, Japanese Utility Model Application Publication (JP-Y) No. 42-13148 that was proposed in advance by the present applicant discloses a slider, in which front and rear post portions are raised back and forth on the slider body and front ends of right and left side wall portions of the pull holding body are rotationally and externally supported by a shaft portion projecting on the right and left side walls of the front post portion against a strip-shaped elastic piece that is protruded on the front surface of the front post portion.
At rear ends of the right and left side wall portions of the box-type pull holding body covering the front and rear post portions on the slider body, pawl portions for locking the slider are formed, respectively, and the pawl portions are inserted and detached with and from a pair of right and left through holes that is formed on the upper surface of the upper blade at the rear side of the rear post portion with communicating with a coupling element guide passage in the slider body. Operating the pull that is movably disposed in the pull housing space portion between the front post portion and the rear post portion through the notch of the pull holding body, the pawl portions of the pull holding body elastically oscillate in a up and down direction around the shaft portion of the front post portion due to the function of the elastic plate of the front post portion, so that the pawl portions are engaged and disengaged between teeth of a fastener chain through the through holes at a side of the rear surface of the rear post portion.
In addition, as another example of a box-type pull holding body of a slider having such an automatic lock function, for example, Japanese Patent Application Laid-Open (JP-A) No. 9-10019 that was proposed in advance by the present applicant discloses a slider, in which a first shaft portion protruded on both right and left side wall surfaces of a base portion of an arched elastic plate is rotatably fixed and supported in the front post portion on the slider body and further, the back and forth of the right and left side wall portions of the box-type pull holding body are externally fitted to the first shaft portion of the elastic plate and the second shaft portion protruding to the right and left sides of a free end portion of the elastic plate, respectively, to be fixed and supported thereto.
Further, as another example of a box-type pull holding body of a slider, for example, JP-A-9-294612 that was proposed in advance by the present applicant discloses a slider having an automatic lock function, which is provided with hook portions at a front surface of a front post portion and a rear surface of a rear post portion that are raised back and forth of an upper blade of the slider body; and with engaging pieces to be engaged and fixed to the hook portions on an inner surface of lower ends of front and rear side wall portions of the box-type pull holding body.
According to the above-described slider disclosed in JP-B-60-30201, as described above, the pivot of the pull is movably mounted in the pull housing space portion that is formed between the front and rear post portions on the upper blade of the slider body; the hook portions protruded at a front surface of a front post portion and a rear surface of a rear post portion and the engaging pieces protruded on the inner surface of the front and rear side wall portions of the platy pull holding body are engaged and fixed; and the engaging pieces of the pull holding body are interiorly fit in and secured to the concave groove portions that are formed from proximal ends at the sides of the hook portions of the front and rear post portions of the upper blade up to the front and rear edges of the upper blade.
According to the above-described configuration, since the engaging piece of the pull holding body is elastically fitted and secured in the fitting space between the hook portion and the concave groove portion of the upper blade, if the lower end edge of the engaging portion of the pull holding body that is fitted in the concave groove is detached from this concave groove due to a large tension load in a right and left direction and an oblique direction against the flat upper wall portion of the pull holding body by the operation of the pull, the engagement of the engaging portion is also disengaged, and the pull holding body cannot return to the foregoing state, so that the pull holding body falls down from the upper blade.
As a result, in order to secure a necessary engagement force on the engaging piece of the pull holding body and the concave groove portion of the upper blade, the fitting portion fitting to the upper blade of the engaging piece of the pull holding body should be made larger, and for this, it is important that the vertical measurements of the fitting portion of the engaging piece is made larger and the depth of the concave groove portion is set deeper as much as possible. If the depth of the concave groove portion of the upper blade is made smaller than the thickness of the engaging piece to a large degree, it becomes difficult to acquire an ideal engaging force between the engaging piece and the inner wall surface of the concave groove. Accordingly, when the depth and the width of the concave groove portion of the upper blade are set smaller than the entire height of the engaging piece, even if the pull holding body and the slider body are reliably and firmly engaged, in the case where a fitting area of the engaging piece and the concave groove portion is small and a strong force occurs to release engagement of the inner wall surface of the concave groove of the upper blade and the engaging piece of the pull holding body upon moving or rotating the pull, the engaging piece of the pull holding body is easily detached from the concave groove because the holding force of the engaging piece by the concave groove against the right and left direction, or the oblique direction, or the up and down direction of the pull holding body is very small, so that this results in that the strong holding force cannot be secured only by the engagement of the engaging piece of the pull holding body and the hook portion of the upper blade.
In addition, assuming that the depth of the concave groove portion of the upper blade is deeper, in connection with this, the thickness of the upper blade should be thicker. However, in connection with setting thickness of the upper blade thicker, the outer measurement of the slider body should also be larger than the size of the concave groove portion and this inevitably involves a problem such that the slider body is made larger entirely.
Further, in connection with setting the slider body larger, the outer measurement of the pull holding body should also be larger and the size of the engaging piece of the pull holding body should be set larger by the height of the fitting space, so that this inevitably leads to make the entire slider larger. Further, in connection with the large pull holding body, the slider does not look well and this involves a problem such that its commercial value is lowered.
In the meantime, when engaging the engaging piece of the pull holding body and the hook portion of the upper blade, it is necessary to move the engaging piece by amounts for clearing a sharp end of a sliding surface of the hook portion while deforming the engaging piece in an enlarging and opening direction against an elastic force. In the case of setting the pull holding body larger as described above, since the size of its engaging piece is inevitably large, en excess pushing force is required to the hook portion of the upper blade. Since such a very large pushing force directly acts on the engaging piece and the hook portion, twist, damage, deformation and the like may easily occur at the engaging piece and the hook portion. In addition, since the elastic force of the pull holding body as the original function is missed, this involves a problem such that assembling characteristic of the slider body and the pull holding body becomes very bad, and the like.
On the other hand, as described above, the sliders disclosed in JP-Y-42-13148, JP-A-9-10019, and JP-A-9-294612 movably hold the pivot of the pull between the notches of the pull holding portion made of a rectangular box body having the ceiling wall portion, front and rear side wall portions, and right and left side wall portions on which the notches are formed at their center portions, and the upper surface of the slider body. The above-described JP-Y-42-13148 discloses the configuration such that the right and left side wall portions of the pull holding body is rotatably fitted in and supported at the shaft portion protruding to the right and left side wall surfaces of the front post portion of the slider body, the above-described JP-A-9-10019 discloses the configuration such that the right and left side wall portions on the back and forth of the pull holding body are fitted in and supported to a pair of shaft portions protruded on the back and forth of the elastic plate, and the above-described JP-A-9-294612 discloses the configuration such that the engaging pieces protruded on the inner surfaces of the lower end portions of the front and rear side wall portions of the pull holding body are fitted in and fixed to the hook portions provided on the forth surface of the front post portion and the rear surface of the rear post portion that are raised back and forth of the upper blade of the slider body.
Assuming that the tractive force of the pull is comparatively small, a lateral slip of the pull holding body may be eased up due to the right and left side wall portions of the pull holding body. However, each of the pull holding bodies disclosed in JP-Y-42-13148, JP-A-9-10019, and JP-A-9-294612 is merely fixed in any one of the right and left direction or the back and forth direction. Therefore, the holding force in any directions such as the right and left direction and the oblique direction of the pull holding body is too small to reliably and firmly assure the engagement of the slider body and the pull holding body while solely receiving the tractive force by the pull from any directions, for example, at the right and left side wall portions of the pull holding body that is miniaturized and thinned. Accordingly, the pull holding bodies disclosed in JP-Y-42-13148, JP-A-9-10019, and JP-A-9-294612 are not changed from the conventional one in that the attachment strength of the pull against the tractive force against the right and left direction or the oblique direction of the pull cannot be expected.
Thus, the technologies disclosed in the above-described respective publications have limitations in improving the attachment strength of the pull against the right and left direction or the like of the pull, so that the ruggedness cannot be secured for a long period. Therefore, the good and stable attachment strength of the pull holding body is strongly required. If this requirement is satisfied, miniaturization of the pull holding body and the slider body can be realized.